A nuclear renogram is performed by injecting a radioisotope into a vein. The isotope flows through the blood vessels of the kidney and is filtered by the glomerulus and/or secreted by the renal tubules. As the isotope flows into the collecting system, it is detected by a nuclear medicine camera usually placed posterior to the kidneys. The amount of isotope filtered and drained by the kidneys can be analyzed by a computer. In this way, perfusion, function and drainage of the kidney can all be determined

Usefulness. A nuclear renogram is useful when questions arise about obstruction of a kidney (hydronephrosis), compromise of a kidney's blood flow, or relative function of a kidney.

Limitations: Nuclear renograms are very sensitive at detecting renal function. However, they have very low resolution. They are really just a collection of black dots. A nuclear renogram may detect obstruction of a kidney, but the films would not indicate the specific anatomy of the kidney, renal pelvis or ureter. An intravenous pyelogram (IVP) would better show such anatomy in a kidney with relatively good renal function.

Indications: A nuclear renogram is useful in evaluating children with hydronephrosis (to determine function of the kidney and to detect obstruction) or abnormal renal parenchyma seen on ultrasound (to evaluate function). Nuclear renograms are very useful in evaluating children with a kidney transplant (to evaluate function).

Examples: Normal kidney. Hydronephrosis.

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©David A. Hatch, M.D., 1996